Guidance on microservices in Elixir using Umbrella

Hi, I'm a little developer, I have an application in Elixir / Phoenix and I need to break the monolithic code in microservices. I have researched how to perform this task using the Umbrella library to create the microservices but I am still lost in how to do this in a practical way, at first I found it easier to create a microservices application from scratch than to create microservices in an existing application, such as is my case.
I would like that someone could give me an orientation in step by step or indicate some content to help me. Thank you.